A variety of tool holders are known in the prior art for holding multiple tools therein for acquisition by a robotic arm. One of such tool holders is taught in U.S. Pat. No. 4,486,928 to Tucker et al which actually employs a plurality of tool holders located proximate to one another at a tool station. Each tool holder includes a plate supported by four corner posts. In one embodiment taught by Tucker et al, an individual tool is inserted into a receiving hole in the plate of the individual tool holder and retained therein through rotation of the tool to effect what is essentially a bayonet mount. In an alternative embodiment, Tucker et al teaches the use of a solenoid actuated clamp to hold individual tools in the individual tool holders.
U.S. Pat. No. 3,816,890 to Cupler, II, teaches a tool positioning mechanism which includes a vertically moveable placement rack supporting a horizontally slidable tool support rack thereon for vertical movement therewith. The tool support rack is horizontally moveable relative to the vertically moveable placement rack in stepwise increments corresponding in distance to the spacing between pre-selected tool support grooves formed in the slidable tool support rack.
U.S. Pat. No. 4,604,787 to Silvers, Jr., teaches an end effector rack for use with a manipulator arm. The end effector rack receives and supports a plurality of end effectors therein so that the manipulator arm can position an end effector in the rack with lateral movement, disengage the arm from the end effector with an axial movement, engage the arm with another end effector by an axially movement in the opposite direction, and remove the new end effector by a lateral movement. The end effector rack includes a plurality of slots in two spaced vertically oriented plates. Each end effector includes a flange which resides between the vertically oriented plates when the end effector is supported therein.
The prior art requires precise positioning of the tools in order to be inserted into their respective tool holders. The prior art fails to teach a compliance mechanism which is self-aligning thereby allowing for a relatively simple tongue and groove mating of the tool within the tool holder.